Logic Fault Detection and Fault Codes. Delta Tau 3Ax-602646-xUxx

Quad Amp Hardware Reference Manual

TROUBLESHOOTING

Logic Fault Detection and Fault Codes

The Quad Amplifier is capable of detecting and reporting a variety of fault conditions. These conditions are broken into two types: axis-specific and global.

Axis-Specific Faults

This type of fault is related to one axis only and typically is not something that would prevent the amplifier as a whole from continuing to operate. These faults are specific to the modules or motors and involve temperature (module or motor), low level ground fault, and over or under current. These faults only disable the axis involved (when they occur and remain active), preventing the axis from being enabled until they actually disappear.

Global Faults

The second type of fault concerns elements critical to the entire amplifier. These faults include heat-sink over-temperature, general power supply faults, bus over-voltage etc. These faults are transient and are latched in the Xilinx gate. The entire amplifier is disabled and remains so, with the fault displayed, until the controller attempts to re-enable it. If the cause of the fault has been remedied, the fault is cleared from the display and PWM is sent to the IGBT modules. If the cause of the fault has not been removed, the amplifier will fault again and disable.

Fault Reporting

Fault conditions are reported in two places. First, the on-board (current sense board) LED displays the fault code as a hexadecimal digit. Second, the fault code is attached to the end of the serial A/D converter data stream being sent to PMAC2 on the A channel of each axis. There is also a fault LED associated with each axis that will illuminate in the case of a fault on the associated axis.

Serial Fault/Status Data

The fault/status circuitry will add six bits to the serial data stream following the twelve bits of serial A/D converter data. The first four bits is the 4-bit fault code; the fifth bit is reserved for the future and sixth bit is the shunt active status bit. The 4-bit fault code sent back to PMAC2 for each axis could reflect either global faults or axis-specific faults on that axis. It will not reflect an axis-specific fault from another axis.

If there is an axis-specific fault and a global fault, the code of the axis with the fault will show the global fault (due to the rule of the higher fault number being reported).

The fault code is accessed in PMAC2 memory via M-variables. For example, the RAM register location

X:$0710 contains Channel 1 ADC1A input image value. Assign M130->x:$0710,8,4 to access 4-bit values only, to read the fault code for channel #1. The following is an example of a PLC that would continuously scan for a Bus under voltage condition.

Close

Delete Gather

M130->x:$0710,8,4

;

Open plc 1

Clear

If (M105=12)

Send “Bus under voltage fault”

Dis plc 1

Endif

Close

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Quad Amp Hardware Reference Manual

Note:

Jumpers E1A, E1B, E2A, E2B, E3A, E3B, E4A, E4B must be installed on the current sense board so that the 4-bit fault code can be accessed at PMAC2 Gate

Array Registers.

Once such a condition occurs, the PLC notifies the user with an on-screen message and then disables itself. Note that C is a hex fault code for Bus under voltage and its decimal representation is 12.

LED Fault Indicator

The fault information is reported as a 4-bit value (0-15 decimal, 0-F hex). A value of 0 indicates no fault.

A value greater than 0 specifies a fault and the number indicates which fault.

Global faults are numbered in the range 8-F (hex). Axis-specific fault codes are numbered in the range 1-

7 (hex). In the case of multiple faults, the higher-numbered fault condition is reported.

If there is no fault condition, the display will indicate a 0. With a 0 in the display, the left decimal point shall be lit if any of the axes is enabled. The right decimal point shall be lit if the internal shunt is active.

The LED fault indicator will provide a following common fault code for the Quad Amplifier:

0

Everything O.K.

1

General firing module fault

2 Module over temperature

3

Ground fault

4

Over current (surge) fault

5 Motor over temperature

6

TBD

7

TBD

8

Heat-sink over temperature fault

9 High PWM frequency fault

A

DAC (nonPWM) fault

B

Bus over voltage

C

Bus under voltage

D General Power Supply/Soft Start fault

E

TBD

F

TBD

Global Fault Only

In the case of a global fault only, the display will indicate the fault number from 8-F (hex). In the case of multiple global faults, the higher numbered fault will be displayed. The decimal point shall be off

(pending possible future use).

Global and Axis-Specific Faults

In the case of an axis-specific fault and a global fault, the global fault shall be indicated.

Axis-Specific Fault Only

In the case of an axis-specific fault on any axis, the display will indicate the fault number from 1-7. The two decimal points shall be used to indicate which axis has the fault in the following manner:

Axis 1:

Axis 2:

Axis 3:

Axis 4:

Left off

Left off

Left on

Left on

Right off

Right on

Right off

Right on

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Quad Amp Hardware Reference Manual

In the case of multiple axis-specific faults on one axis, the higher-numbered fault shall be indicated.

In the case of axis-specific faults on multiple axes, the axis with the higher-numbered fault shall be displayed along with the decimal point indicting its axis number.

In the case of axis-specific faults of the same number on multiple axes, the fault number shall be displayed and decimal point indication shall specify the higher-numbered axis.

Problem Check

Under voltage indicator comes on when power is applied.

This is a normal condition. When AC power is first applied, the Soft Start has not been initialized and the bus is not charged. This results in a low line fault. The first enable command (usually o0) will initialize the Soft Start. The following CNTL K command will ensure that no motor is enabled. It will also turn the Soft Start IGBT on and allow the bus cap to charge.

Quad Amplifier enables normally but

LED Fault Indicator displays C after a

Check if the bus voltage holds steady after an axis is enabled and/or moved motor is moved.

Motor does not turn. 1. Is the correct main AC power applied to the unit?

Apply correct AC power.

2. Is a motor connected? Connect

3. Is the power enable (E-Stop) switch closed at C1?

Close E-Stop switch. (If E-Stop not used, make sure a plug is installed on connector C1.)

4. Is PMAC2 connected, powered and working?

5. Is the correct axis being commanded?

6. Is there a fault indicated on the

LED Fault Indicator?

Connect, power up or replace PMAC2 if necessary.

Command the correct axis.

Refer to the LED Fault Indicator fault codes and take the corrective action.

Warning:

At this point, it is necessary to remove the Quad Amplifier cover to further troubleshoot the unit. Every precaution should be taken to avoid serious injury from being exposed to high voltages.

7. Is there a bus voltage?

8. Are all logic supply LEDs (D5,

D6, D7) on the logic and current sense boards lit?

9. Is the commanded axis enable

LED (D18-D21 on logic board) lit?

Make sure the AC power is applied and check for

DC bus voltage across 15 k Ohm bleed resistor on the filter capacitor box.

An unlit power supply LED means that a supply is bad or missing. Check AC voltages at J5 of the Quad Amplifier logic board. Check if the cable between the logic board and the current sense board is connected.

Generally, enable LED comes on after #xo0 command. Check if Ix00 is 1.

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Quad Amp Hardware Reference Manual

Motor moves after a command is issued but under voltage fault comes on shortly after.

Also, the Soft Start resistor heats up (and possibly burns).

Under voltage fault stays displayed even after several enable commands.

Verify if the bus voltage sags when the motor is commanded to move.

The Main IGBT probably does not turn on. Check if the wiring between

E1 and G1 (of Main IGBT) and J4-5, -

6 (Soft Start board) is okay. Then verify if G1 with respect to E1 switches from approx. –10 VDC to

+15 VDC after the Main power is turned on. If it does, the Main IGBT is probably open. If it does not, the problem is most likely with the Soft

Start board.

Check if there is bus voltage across

15k Ohm bleed resistor.

Call Delta Tau for an RMA.

If not, examine if the 10-pin flat cable between the Soft Start and the I/O Logic board is connected on both sides and in good shape.

32 Troubleshooting